Haley said while with the Arizona Cardinals he spent an extended period of time talking with him at the NFL Combine.
"Mo [Carthon] and I had been together and we watched a lot of tape on him," Haley said. "We took a lot of time with him and thought we had a chance to get him there. We thought he had a chance to be a good back.
The Chiefs used the 73rd selection in the draft on Charles. The Cardinals were picking 81st.
"Some of these guys just don't know until they're under the fire," he said.
Haley wouldn't say whether Charles had exceeded his expectations this season but starting out as a backup, I don't know how he could have done much better in the time allotted.
"Jamaal's the one that continues to push the expectations and that's good," he said. "I think that's what has everybody excited."